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Full text of "The manufacture and properties of iron and steel"

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218
METALLURGY OF IRON AND STEEL.
17 heats  below                   .10  per  cent.
45      "     between .10  and .20    "     "
10      "           "        .20    "    .30    "      "
6      "           "        .30    "   .40    "      "
2      "           "        .40    "    .60    "      "
1 heat    not given.
80
The slags from the primary furnace contained from 20 to 23 per cent, of phosphoric acid and the following proportions of iron (Fe) :
4 heats between    6 and    7 per cent.
22  "	7 '	<  8 "
16  "	8	9 "
12  "	9	10 "
7  "	10	11 "
2  "	11	12 '
1 heat	12	13 '
4 heats	13	14 '
8  "	14	15 '
1 heat	17	18 '
8 heats        not given.
80
During two weeks the furnaces made an average per twenty-four hours of 7.6 heats of 12.3 tons each, or 94 tons per day for the two furnaces, the maximum capacity of the larger being 13 tons. The phosphorus in the steel was as follows:
18 heats .below .01 per cent.
24 21
8 2 4 1 1 1
between .01 and .02 per cent.
heat
.02 .03 .04 .05 .07 .08 .11
.03 .04 .05 .06 .08 .09 .12
In a private communication from Mr. Bertrand I received cor-rohoration of the foregoing practice and he gave the results on two heats, one made from an iron with about 1.30 per cent, of silicon, and the other with 0.50 per cent. The higher silicon necessitates a larger addition of lime and reduces the phosphoric acid in the slag from the primary furnace, this being an objection when the slag is to be sold as a fertilizer. The results are given in Table XII-F. Mr. Bertrand states that manganese in the pig-iron has an important bearing on the elimination of phosphorus, and saves time, as the slag is more liquid and the hearth remains cleaner after tapping. When there is no manganese in the pig-iron the phos-